(a) FIELD of the Invention
The present invention relates to a function mode switchable remote control device so adapted as to be capable of switching remote control functions allocated to operation keys with a function switching means and displaying functions of various modes on a remote control transmitter
(b) Description of the Prior Art
On the transmitter in a remote control device used with the audio apparatus or TV set, a single function is generally allocated to each operation key. On a remote control transmitter capable of switching function modes, in contrast, a plural number of functions are allocated to a single operation key and function modes are switched with a function selector switch or the similar means. By switching the function modes, a code or a signal to be transmitted by operating the same key is switched so that a main apparatus controlled by the transmitter performs a different function. Such function switching is utilized, for example, to diversify functions without increasing the number of operation keys or to modify arrangement of the keys.
In case of function switching of the operation keys, a problem lies in the way how to simplify the formation and how to make legible the display of the functions of the individual keys. As the conventional methods for displaying the functions, it is known to mark the plural functions in various modes in the vicinity of the individual keys and, also known to dispose a display in the vicinity of the individual key and switch the display in response to the function mode switching on LEDs (light emitting diodes) or LCDs (liquid crystal displays).
However, the above-mentioned method to mark plural functions in the individual keys has a defect that the markings are crowded and not legible, thereby making the markings rather inconvenient for practical use. On the other hand, the display using the LEDs or LCDs has a drawback that it requires a display circuit, etc., thereby being complicated in formation and high in the price thereof. Further, the numbers of operation keys and electrical circuits are increased, and formation of the display is complicated when it is attempted to design a display in such a manner that it permits a user to freely set or modify functions of the operation keys. Moreover, the display of the latter type requires a power source, which is usually storage batteries having a short service life and turned off for energy saving while the main apparatus is rested, thereby producing inconvenience that said display does not allow a user to read out the functions of the operation keys at a glance when the power source is turned off.